20897897 has 4 divisors (see below), whose sum is σ = 20946816. Its totient is φ = 20848980.

The previous prime is 20897873. The next prime is 20897909. The reversal of 20897897 is 79879802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20897897 - 2¹⁰ = 20896873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20897827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23813 + ... + 24674.

It is an arithmetic number, because the mean of its divisors is an integer number (5236704).

Almost surely, 2^20897897 is an apocalyptic number.

It is an amenable number.

20897897 is a deficient number, since it is larger than the sum of its proper divisors (48919).

20897897 is an equidigital number, since it uses as much as digits as its factorization.

20897897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48918.

The product of its (nonzero) digits is 508032, while the sum is 50.

The square root of 20897897 is about 4571.4217700842. The cubic root of 20897897 is about 275.4445569879. Note that the first 3 decimals are identical.

The spelling of 20897897 in words is "twenty million, eight hundred ninety-seven thousand, eight hundred ninety-seven".